This application claims priority under 35 U.S.C. § 119(a) on Japanese Patent Application No. 2007-147081 filed in Japan on Jun. 1, 2007, the entire contents of which are herein incorporated by reference.
An aspect of the present invention relates to a toner cartridge and an image forming apparatus.
Image forming apparatuses that form images using an electrophotographic method are capable of forming a high quality image with a simple operation, and also maintenance of such image forming apparatuses is easy, so such image forming apparatuses are becoming widespread, being used heavily in copy machines, printers, facsimile apparatuses, and the like. An electrophotographic image forming apparatus ordinarily forms an electrostatic latent image on an electrostatic latent image carrier such as a photosensitive drum, develops the electrostatic latent image with a development apparatus using a toner supplied from a toner discharge apparatus provided in the development apparatus to the development apparatus by rotation of a toner discharge roller, transfers a toner image to a recording medium such as recording paper with a transfer apparatus, and fixes the toner image on the recording medium with a fixing apparatus.
In this sort of image forming apparatus, consumed toner and recording media can be replenished by a user as necessary. Of these, toner is replenished to the toner discharge apparatus by the user, but there is the problem that because toner is made up of extremely light and fine particles, when replenishing toner to the toner discharge apparatus, toner scatters into the air and the user's hands become dirty.
As a response to this problem, a technique has recently become mainstream in which, such that toner particles do not scatter into the air, a toner cartridge having the function of a toner discharge apparatus is installed in the image forming apparatus, and the toner cartridge is exchanged as-is; that is, a toner cartridge that has become empty is removed from the image forming apparatus and a new toner cartridge is installed. Due to recent increasing awareness of environmental problems, it is often the case that the empty toner cartridge is reused and not discarded, so the empty toner cartridge is shipped after being cleaned and filled with new toner.
In this sort of toner cartridge, a toner discharge port is provided in order to discharge toner from the toner cartridge to the development apparatus. Accordingly, there is a risk that during transportation by a transportation means such as a boat or a vehicle, toner stored in the toner cartridge will leak out from the toner discharge port. Thus, conventionally, a method has been adopted in which toner leakage is prevented during transportation by plugging the toner discharge port with a heat seal. However, there is the problem that with a toner cartridge in which the toner discharge port has been heat sealed, when installing the toner cartridge in an image forming apparatus, it is necessary to remove that heat seal, and when removing the heat seal, toner scatters and hands of the user become dirty.
In order to address such a problem, in JP H6-11967A for example, a toner cartridge has been proposed in which a toner discharge roller that has a passage prevention portion of vinyl or the like that prevents passage of toner is disposed at the toner discharge port of a toner storage container. Also, JP 2003-84557A discloses a toner cartridge in which a seal member is disposed between a toner discharge roller and a toner discharge port.
However, with the toner cartridge described in JP H6-11967A and JP 2003-84557A, the case is such that during transportation by a transportation means such as a boat or a vehicle, when the toner storage container in which toner is stored receives vibration for a long period of time, or receives a large vibration, toner enters between the passage prevention portion of the toner discharge roller and the inner wall of the toner storage container, or between the seal member and the inner wall of the toner storage container, and leaks from the toner discharge port.
In this toner cartridge described in JP H6-11967A and JP 2003-84557A, in order to prevent toner leakage during transportation, it is conceivable to increase the pressing force of the toner discharge roller against the inner wall of the toner storage container, thus causing the toner discharge roller surface to fit closely to the area around the toner discharge port, but when the pressing force of the toner discharge roller is increased in this manner, frictional resistance between the toner discharge roller and the inner wall of the toner storage container becomes large when the toner discharge roller rotates in order to use the toner cartridge (that is, in order to discharge toner from the toner discharge port), and thus there is frictional wear on the toner discharge roller. Consequently, performance of the toner discharge roller decreases, and in that state it is not possible to reuse the toner cartridge.